Study of the Efficacy and Safety of Immune Globulin Intravenous (Human) Flebogamma 5% DIF in Patients With Post-polio Syndrome

Brief description of study

This is a multicenter, prospective, randomized, placebo-controlled, double-blind, parallel
group clinical trial with adaptive dose selection in subjects with post polio syndrome (PPS).

The main purpose of this study is to select a dose of Flebogamma 5% DIF and confirm the
efficacy of the selected Flebogamma 5% DIF dose by assessing physical performance, as
measured by 2 Minutes Walk Distance (2MWD) test.

The study will consist of 2 stages, with each stage consisting of a screening period (up to 4
weeks), a treatment period (52 weeks), and a follow-up period (24 weeks).

Detailed Study Description

This is a phase II/III multicenter, prospective, randomized, placebo-controlled,
double-blind, parallelgroup clinical trial with an adaptive design (flexible group
sequential design with adaptive dose selection) in subjects with PPS.

This study will consist of two stages. The first stage (Stage 1) is for dose selection, and
the second stage (Stage 2) is to establish the superiority (efficacy confirmation) of
Flebogamma 5% DIF and for overall safety analysis. Stage 1 is a 3-arm evaluation of 2 dose
levels of Flebogamma 5% DIF. Flebogamma 5% DIF 2 g/kg of body weight (IVIG 2 g/kg arm), or
the equivalent volume of Normal Saline Solution (40 ml/kg of body weight), or Flebogamma 5%
DIF 1 g/kg of body weight plus the equivalent volume of Normal Saline Solution (20 ml/kg of
body weight) (IVIG 1 g/kg arm) will be administered every 4 weeks over 2 consecutive days
during a 52-week treatment period. At the end of Stage 2, an interim analysis will be
conducted and 1 of the 2 Flebogamma 5% DIF doses will be selected based on predefined
criteria to be used for Stage 2 .

Stage 2 will consist of 2 treatment arms, the selected dose of Flebogamma 5% DIF from Stage
1 and Normal Saline Solution (40 ml/kg of body weight). Study drug will be administered every
4 weeks over 2 consecutive days during a 52-week treatment period. During Stage 2, the
selected dose of Flebogamma 5% DIF and Normal Saline Solution will be administered in the
same manner as in Stage 1, including administering the total dose for both treatment arms at
a volume equivalent to that for the IVIG 2 g/kg arm, regardless of the selected dose.

Primary efficacy endpoint will be:

Physical performance (2MWD) from baseline to the end of the treatment period (at End of
Treatment Visit -Week 52).